Fort Meade: A military judge refused on Thursday to dismiss the most serious charge against the Army private who gave reams of classified information to the anti-secrecy website WikiLeaks.

The charge of aiding the enemy faced by Pfc. Bradley Manning is punishable by up to life in prison without parole. Colonel Denise Lind, the judge in Manning's court-martial, denied defence requests to drop that charge and a computer fraud charge, ruling that the government had presented some evidence to support each element of the charges.

Lind is still considering defense motions to acquit Manning of five theft counts. To convict Manning, the government must prove the charges beyond a reasonable doubt; however, they had to meet a less stringent standard in convincing Lind that the charges should stand.

Manning has pleaded guilty to reduced versions of some charges. He faces up to 20 years in prison for those offences.

The 25-year-old has acknowledged giving the anti-secrecy group hundreds of thousands of Iraq and Afghanistan battlefield reports and State Department diplomatic cables, along with battlefield videos and other documents.

He downloaded them in late 2009 and early 2010 from a classified government computer network while working as an intelligence analyst in Iraq. WikiLeaks posted much of the material on its website.

The government charged Manning with aiding the enemy, claiming he knew the intelligence published online would be seen by al-Qaida members. Prosecutors produced evidence that al-Qaida leader Osama bin Laden obtained digital copies of some of the leaked documents WikiLeaks published.

The government also charged Manning with espionage, computer fraud and theft.

Manning has said he leaked the material to provoke public discussion about what he considered wrongdoing by American troops and diplomats. The material included video of a 2007 US Apache helicopter attack in Baghdad that killed 11 men, including a Reuters news photographer and his driver. A military investigation concluded the troops reasonably mistook the photography equipment for weapons.